TM 9-2320-209-10-1 4-19. OPERATING THE ELECTRIC BRAKE KIT. NOTE The electric brake kit is installed on trucks used to move trailers or semitrailers. WARNING Electric brakes on towed trucks operate when service brake pedal is pressed down, not when rheostat control handle (1) is turned. Make sure brakes work correctly at the number you set on the rheostat. Failure to make sure brakes work correctly may result in injury to personnel and damage to equipment. 1. Turn rheostat control handle (1) to setting shown on data plate (2). NOTE Exact setting needed for each load must be found by experience. Heavier loads need higher number setting. 4-403